Butterfly valve



FIG. 1 is a front perspective view of a butterfly valve showing my new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a cross sectional view taken on line 7--7 of FIG. 1; and

FIG. 8 is a cross sectional view taken on line 8--8 of FIG. 1. 

The ornamental design for a butterfly valve, as shown. 